Cylinder etching machine



P 1950 c. HENDERSON 2,523,019

CYLINDER ETCHING MACHINE 4 Sheets-Sheet 1 Filed Aug. 6. 1947 Q1! mN QT Sept. 19, 1950 c. L. HENDERSON 2,523,019

CYLINDER ETCHING MACHINE Filed Aug. 6. 1947 4 Sheets-Sheet 2 I l l h H HI I I I I l I I I I I l I I II .I I w 3 llllllll l m i HHHHHJ U Q lllllllllll Q h lllllll m n gm Y Q h n J i an x. g fi v mu l1? mm mh g ms, m fi fi l hl l h mfl l w l l l p ha W lllllll IIL K V @QWW P 1950 c. HENDERSON 2,523,019

CYLINDER ETCHING MACHINE Filed Aug. 6. 1947 4 Sheets-Sheet 5 .Zn 2/192 507: C75 arZes lfifzci'errorz g gar-(away P 1950 c. HENDERSON 2,523,019

CYLINDER ETCHING MACHINE Filed Aug. 6. 1947 4 Sheets-Sheet 4 rang Jam, A 414 wm Patented Sept. 19, 1950 CYLINDER ETCHING MACHINE Charles L. Henderson, Appleton, Wis, assignor to Paper Patents Company, Neenah, Wis., a corporation of Wisconsin Application August 6, 1947, Serial No. 766,805

(Cl. 4l-9) 6 Claims.

The present invention relates particularly to improved apparatus for etching intaglio or relief printing cylinders.

In intaglio printing the printing surface ordinarily comprises a smooth, metallic surfaced cylinder, usually of copper, having etched therein, symmetrically arranged ink-receiving recesses of very small area. The ink recesses throughout the printing surface are separated by line-like, unetched lands, which serve to support the doctor or scraper blade used for removing excess ink from the printing surface during the actual printing operation.

Various methods and procedures have been developed for etching printing surfaces. For example the etching machine and method disclosed in my prior Patent 2,360,676, makes possible continuous mechanical etching procedures which provide a uniformly etched surface. The etching machine and method disclosed in my co-pending application Serial No. 715,893, which was filed on December 12, 1946, and which is assigned to the assignee of the present invention, also provides an apparatus and method whereby the progress of etching a printing surface is closely controlled, so that a more uniformly etched surface having more accurate tonal quality will be produced. Both of my prior machines provide means for efficiently and accurately etching printing cylinders which are of substantially regular sizes.

In some printing processes, however, it is necessary to etch cylinders of widely varying diameters and lengths, for example, it may be necessary to etch cylinders having diameters ranging from less than about 3 inches to more than about 14 inches, and the provision of apparatus for this purpose constitutes the principal object of the present invention. This object is accomplished by the provision of an etching machine which includes means for quickly and accurately positioning the printing cylinder to be etched and means for rapidly adjusting the area which is eX- posed to the etching fluid. Thus, the high quality etched surface of my prior procedures may be consistently produced on irregularly sized cylinders. Other objects and advantages of the invention will be made clear upon reference to the accompanying drawings and the following description of one preferred embodiment thereof.

In the drawings,

Fig. 1 is a fragmentary, side elevational view, partially in section, of an etching machine constructed in accordance with the present invention;

Fig. 2 is an end elevational view taken on line 2-2 in Fig. 1;

Fi 3 is a sectional View taken on line 33 of Fig. 1;

Fig. 4 is a sectional view taken on line 4-4 of Fig. 1;

Fig. 5 is an enlarged, sectional view taken on line 5-5 of Fig. 1;

Fig. 6 is an enlarged, fragmentary view taken on line 6-6 of Fig. l;

Fig. 7 is a sectional View taken on line 1--1 of Fig. 6;

Fig. 8 is a. fragmentary, elevational view of a modified form of air nozzle for use with apparatus of the present invention; and

Fig. 9 is a sectional View taken on line 9-9 of Fig. 8.

The etching machine illustrated in the drawings, as before pointed out, is designed, particularly, for etching printing cylinders of widely varying sizes. The etching machine generally comprises a relatively heavy frame structure, a pair of bearings, vertically adjustably supported on columns, for rotatably supporting the printing cylinder which is to be etched, means for rapidly and accurately adapting the supporting columns to printing cylinders of varying sizes, means for rotating the printing cylinder, a container for the acid or other etching fluid, means for applying the fluid to the printing cylinder, and means for controlling the area on which the etching fluid acts. In the present machine, narrow, carefully directed streams of pressure air are utilized to limit the area of the cylinder subjected to the action of the etching fluid, and these air streams are adjustable so that they may be directed against the cylinder, during the etching opertaion, along a line which is normal to the surface of the cylinder. The surface being etched comes in contact with only etching fluid and the pressure air from the air streams.

The frame structure illustrated includes a heavy rectangular frame II which is supported upon upright members it. The frame members I I and [3 are desirably of relatively heavy structural steel and are covered with an acid-resisting coating at all points where there is possibility of contact with the etching fluid. Suitable platforms are included on the frame II to provide support for the driving motors and other associated apparatus. The frame II is enclosed by suitable plate members I4 which form a casing about the frame H and the elements supported thereon. Suitable hinged panels iii are provided on each end of the machine to permit access to the mechanism which is enclosed by the casing. Flared, upwardly extending sheets iii are attached to each end of the apparatus to prevent etching fluid from splashing onto surrounding working spaces.

an etching fluid or acid tank ill extends 1ongitudinally to the frame and is supported at its ends and at various points along its length, as necessary, to provide a rigid structure. The acid tank is desirably shaped as illustrated in the drawings, and has a longitudinally extending shell portion ll having an arcuate section it extending for approximately 260 around the bottom of the shell. The ar'cuate section is con verges to form a longitudinally extending throat 23,. he ends 255 of the acid tank 55 are plane surfaces and are desirably bolted to the longitudinal shell portion ll. The acid tank ends 25 are attached to the end members of the rectangular frame H. An acid inlet 2"? is provided in the bottom of the acid tank 55, as illustrated in the drawings. The inner portion of the tank l5 and the acid inlet 2i should be covered by a suitable acid-resisting material 26 as, for example, a A; to /4 -.ch coating of pure, black gum rubber or a suitable acid-resisting paint or cement.

A large circular portion 28 is cut out of each oi the end sections to provide access to the interior of the acid tank A5 for removing or servicing an impeller member 29 which is to be l ereinafter described. The openings resulting from the cut-out portion are sealed by removable plate members 3! Which are provided with bearings for rotatably supporting the shaft for the impeller A seal between the plate members and the end sections of the acid container i5 is provided by extending the rubber or other acid-proof coating provided on the inner surface of the acid container is to a position under the plate member 3 i. This seal insures that the metal will not be exposed to the action of the etching fluid.

The acid, or other etching fluid, indicated at n 5, is atomized and applied to the surface which is to be etched by means of the rotatable '"npeller member 29. The impeller 29 comprises a series of paddle members made from an acidresisting plastic, or some other acid-resisting material. The paddle members 35 are affixed to suitable rotatable shaft 3?, and one end of the shaft extends through an opening in one end of the acid tank l5 for connection to a motor 3%) or other rotating means. If it is desired, a curved, fixedly positioned, deflector, as shown in application Serial No. 715,893, may be used i conjunction with the impeller 29 to direct the acid spray upward against the surface to be etched.

The impeller 22 is supported for free, high speed rotation within the acid container by the bearings in the plate members 35. Desirably, the ngs for the impeller shaft 3's are provided a suitable acid proof seal such as the pressure air seal disclosed in my application Serial No. 715,893.

The motor 351 which is used for rotating the impeller it is supported on a bracket ll affixed to one of the frame uprights l3, and is connected to the impeller shaft 3? by a belt (is and suitable pulleys and The impe ler 29 should be rotated at relatively high speed in order to accomplish good atomization and an even distribution of the etching fluid along the surface which is to be etched. Impeller speeds upwards of about 1299 R. P. M. have been found to be satisfa ory.

rotatably supported on the frame ll.

The acid tank i5 is surrounded by an air jacket %8 fabricated from sheet material. The air jacket it is shaped to conform with the shape of the acid tank i5, and is large enough to allow for the free circulation of air around the outside of the acid tank as is shown b the arrows 19. The air jacket ill is conveniently attached to the upper end of the acid tank It; by means of a suitable spacer-bracket and bolt assembly to (Fig. 5) The blower 53 is adapted to be powered by a motor 55, and both the motor 55 and the blower 53 are .ipported on a suitable frame 5?.

The air streams or blasts, which remove etching fluid from the cylinder being etched and which determine the area of the cylinder subjected to the acid spray, emanate from a pair of spaced-apart, adjustably supported, longitudinally extending, air nozzles 59. The air nozzles are located adjacent the outlets of the air jacket 58 and form a continuation thereof. Each of the nozzles is fabricated from a pair of longitudinally extending, rigid plate members 6!, desirably of acid-resisting metals which are joined together at each end by a suitable connecting member which closes off the ends of the plate members El. Each of the connecting members includes an outwardly extending journal section 55 which is adapted to be supported in suitable bearings on the frame H. The connecting members thus support the nozzles 59 so as to permit limited rotation thereof; the connecting members 63 also determine the spacing of the opening between the longitudinally extending members E l. The outlet of each of the air nozzles 53 comprises a slot El of uniform width. Normally the width of the slot 6? is fixed, it being in the range of from about .005 inch to about 1115 inch when the air pressure in the air jacket is maintained at about 4 pounds per square inch.

The base portion of each of the air nozzles 59 is resiliently connected to the air jacket by means of an elongated, flexible connecting member 59 of rubber or the like (Figs. 6 and 7). The flexible connecting member 89 is rectangular in cross section and is proportioned so that it is wedged tightly between the side members of the air jacket (.3 and the acid container lll when in place therein. The upper end of the flexible connecting member 69 fits within the base of the air nozzle 53 (Fig. 6). Generally vertically extending holes ll are provided in the flexible members G9 so that the pressure from the air jacket 58 is allowed to pass freely into the nozzles The resilient connection provided by the flexible member 5?; permits relative angular movement between the air nozzle 5d and the air jacket 63, in response to the adjusting means which locates the nozzle 5%; for cylinders or varying sizes.

The adjustment of the direction of the air streams is one of the important features of the present invention. In order to permit such adjustment, a gear segment '53- is attached to each end of the outwardly extending journal sections 35 on one of the air nozzles 55) by means of suitable keying members, and cooperating segments it are keyed to the outwardly extending journal sections 65 on the other air nozzle 59. The gear segments and it are proportioned and disposed so that they mesh along the center line 0;" the machine, as illustrated particularly in Fig. 3. Adjustment of the direction of the air nozzles 59 is effected by means of a longitudinally extending control rod "i5 which is A pair of pinion gears ll adapted to mesh with the two gear segments I3 are keyed to the control shaft I5. A worm wheel I9 is also attached to the shaft I5, and this Worm wheel '19 is operatively engaged by a worm 9I whose shaft 83 is rotatably journaled into a bearing 94 on the frame. An adjusting crank or knob 85 is connected to the worm shaft 83 for positioning the air nozzles 59.

One end of the control shaft I5 extend adjacent the end panel I6 of the machine, and is conveniently provided with a pointer 99 for indicating the position of the air nozzles 59.

It is apparent that positioning one of the noz- Zles 59 will automatically position the other nozzle 59 by virtue of the intermeshing connection between the gear segments I3 and I l. The provision of uniform, adjusting torque at each end of the machine is especially desirable, as the balanced application of adjusting force insures that the air nozzles 59 will not warp and that they will deliver an even blast of air to the cylinder being etched. A suitable transparent viewing window 9| is provided in the outer end panel I6 adjacent the end of the control shaft F5 for observing the pointer 89. This window 9| may be scribed with indicating marks 93 for showing the various positions of the air nozzles 59 which correspond to normals to the surfaces of various sized printing cylinders (Fig. 2)

In order to control the level of the etching fluid 33 in the acid tank I5, an adjustable height, filling-container 95 is provided. The container 95 is vertically, adjustably fastened to a bracket 97 on the frame II and is connected to the inlet 2'! of the acid container I5 by means of a gum rubber or other acid-resisting, flexible hose In order to closely control the level of the etching fluid 33 in the acid tank I5, it is desirable to provide a constant level overflow I9I which may be connected to an acid recovery tank by means of a hose I93. All the surfaces of the filling-container95- are covered with an acidresisting coating. It is advantageous if one of the sides of the container is formed into a spout or guide I95 so that the etching solution may be conveniently poured from the filling container 95 when it is desired to drain the acid from the main acid tank I5.

The cylinder etching machine of the invention includes adjustable means for accommodating cylinders of widely varying dimensions and, in the particular machine shown in the drawings, this means includes an adjustable bearing support structure for the cylinder I9! which is ed with low pitch threads I I3, and these are connected by a suitable worm and Worm wheel linkage to a hand crank H6 which simultaneously moves the two screw jacks I99 upwardly or downwardly. The linkage includes a pair of fixed bearing blocks II5, one of which is attached to each end of the main frame II adjacent the threaded portion I I3 of the screw jacks I99. Each of the bearing blocks II5 includes a horizontally extending slot II! in which is confined a worm wheel H9 which has a central threaded hole for operatively engaging the threaded portion II3 of the screen jack I99. A control rod I2I which extends longitudinally the main frame II, is

6. journaled for rotatable movement in the fixed bearing blocks H5, and a pair of control worms I23 which engage the periphery of the worm wheels II9 are keyed to this control rod. The control crank IIB is connected to one end of the control rod IZI so that the position of the screw jacks I99 may be simultaneously adjusted in a vertical plane. An indicating member I25 is attached to the screw jack adjacent the hand crank II6 so that the operator may accurately position the bearing yokes I I9 before the cylinder I9! is placed in the etching position. In this connection a viewing Window I21 in the hinged end panel I6 is calibrated to the diameter and circumference of the cylinders being etched so as to permit the rapid and accurate pre-setting of the bearing support yoke I I9. I

The adjustment of the distance between the surface of the cylinder I91 being etched and the outlet of the air nozzles 59 is a most important adjustment in the successful operation of the etching machine of the invention. Usually a spacing of from about to & of an inch will be found satisfactory in the illustrated apparatus, with the air slots that have been described. In place of the manual operation by means of the hand crank I I5, hydraulic or poweractuated jacks may be used.

A motor I29 for rotating the cylinder I91 which is to be etched is supported on the plate or door I9 on a suitable support bracket I3I. A pulley I33 on th motor drive shaft is operatively connected to a pulley I35 which is adapted to fit on the cylinder shaft by means of a belt I31. In order to rapidly adapt the equipment to printing cylinders of varying diameters it is desirable to provide a spring-biased, belt take-up arrangement which allows rapid changes in the effective length of the drive belt I31 without altering the position of the driving motor I3I. In th illustrated structure this is accomplished by the provision of a fixed idler pulley I39 and a movable idler pulley I4I which is slidably engaged between a pair of generally vertically extending tracks I43 (Figs. 1 and. 4). The block for the pulley I4! is connected by means of a flexible chain I45 to a sprocket I41 which is biased by means of a tensioned spiral spring I49. The entire assembly is protectively surrounded by a shield I5I which is provided with a curved central guard I53 adapted to support the belt I31 when it is not disposed around the pulley I35 on the printing cylinder II".

To start the machine in operation, the acid or other etching fluid 33 is poured into the filling container until the liquid level in the acid tank I5 is high enough for the impeller blades 35 to dip into the acid about A; of an inch at the lowest position in their are of travel. The cylinder I91 which has a set of ball bearing rings I55 on its shaft is cradled in the yokes III] provided for the bearings on the adjustable screw jacks I99. The height of the yokes H9 is adjusted so that the distance between the air slot 61 and the surface of the cylinder is from about h to of an inch. The air nozzles 59 are then positioned so that they are normal to the surface of the cylinder III! to be etched. Since the control means are provided with suitable indicators which are calibrated in accordance with the dimension of the cylinders to be etched, the air nozzles 59 and the bearing yokes II 0 may be positioned prior to cradling the cylinder shaft in the supporting yokes and the operation of changing cylinders is thus greatly expedited.

When the cylinder is in place th cylinder driving motor i=2!) may be energized to rotate the cylinder at the proper rate. The speed is constant. Next the air blower 53 is started and the impeller 29 isenergized to atomize theetching fluid. The etching is continued until the ink-receiving recesses have been etched to the required depth, whereupon the impeller 29 is then stopped and the cylinder II is rotated in the air blast until it is dry.

When etching relatively short cylinders it will be found desirable to partially cover both ends of the acid tank l5 with an acid-resisting, removable baflle I51, as illustrated in Fig. 5. The bafile i5? is desirably a thin sheet of acid-resisting material which can be snapped into position in the throat of the acid tank l5 wher it will be supported upon the spacer brackets 59 which are used to connect the acid tank shell I7 and the air jacket 38. In order to facilitate the removal of the baiile members l5l, suitable handles H16! are provided on the upper surface thereof. This arrangement confines the discharge of the etching fluid to the length of the cylinder which is to be etched.

A modified air nozzle structure is illustrated in Figs. 8 and 9; this structure is essentially equivalent to the air nozzle 59 which has been described in the foregoing, and under certain conditions it may be preferred. In the modified air nozzle 5%. the air is conducted into a longitudinally extending tube member it! at one or both of its ends. Th tube 56! is provided with a series of holes I63 which open into the lower portion of the space between a pair of conveying plate members 6512 which define a longitudinally extending air slot Gila. In order to permit movement of the nozzle 5.9a relative to the shell ll of the-acid tank i5, a flexible air lead N55 is provided. outwardly extending journal sections 65a are attached to each end of the tube i6! and gear segments (not shown) are keyed to the outer ends of the journal section 65a. For the purpose of providing an acid-proof seal between the acid tank l5 and tube the inner lining 26 of the acid tank i5 is extended upwardly and attached to the inner nozzle plate member tic (Fig. 8;). The modified air nozzle structure 59a eliminates the need'for an air jacket 48 and thereby reduces the over-all cost of the equipment.

In the foregoing, there ha been described a cylinder etching machine which is capable of producing gravure cylinders of extremely high quality with a minimum expenditure of time and labor. The doctoring-ofi of the etching solution is rendered extremely eflicient because of the provision for close and accurate spacing between the air nozzle and the surface of the cylinder, and the provision of means for directing the air blast along a line which is normal to the surface of the cylinder being etched. The indicating means which cooperate with control means for adjusting the direction of the air streams and the position of the cylinder make possible the accurto produce streams of air which flow out of said air slots and are directed against the cylinder at spaced intervals on the periphery thereof during the operation of the apparatus, means for applying a spray of etching fluid to the surface of the cylinder in the region intermediate said air streams, means for rotating the cylinder during the etching operation, and means including an adjustable mounting for said air slots for controlling the direction of said air streams whereby said streams are directed substantially normal to the surface of said cylinder.

2. In combination in apparatus of the class described, means for supporting a cylinder which is to be etched for rotation about its longitudinal axis, means for rotating said cylinder during the operation of the apparatus, means operable to direct a spray of etching fluid against the surface of said cylinder during the operation of the apparatus, and means for restricting the surface area of said cylinder exposed to said etching fluid and for doctoring off etching fluid from the surface of said cylinder, said means including a pair of adjustably supported, spaced-apart, generally parallel air nozzles which extend longitudinally of said cylinder and through which air streams are directed against the surface of said cylinder, and a control linkage interconnected With each of said adjustably supported air nozzles for simultaneously positioning said nozzles to cause said air streams to impinge upon the surfaces of various size i cylinders along lines defined by extended radii of said cylinder.

3. In combination in apparatus of the class escribed, adjustable means for supporting a cylinder which is to be etched for rotation about its longitudinal axis, means for rotating said cylinder, means operable to provide a spray of etching fluid which is directed against a portion of the surface of said cylinder being etched, including an elcngated tank which contains etching fluid and which has an elongated, relatively narrow throat means for atomizing the etching fiuid within said tank, and means for doctoring off etching fluid and for confining the etching fluid spray to a predetermined portion of the surface of the cylinder which is being etched, sai last mentioned means including a pair of spaced-apart, elongated, horizontally extending air nozzles, means including an adjustable mounting for said air nozzles intermediate the throat of said acid tank and surface of the cylinder being etched, a strip of flexible material interconnecteach of said nozzles with said tank, a source of pressure air, and means for connecting said source of pressure air to said nozzles.

4. In combination in apparatus for etching printing cylinders of varying sizes, adjustable means for supporting the cylinder which is to be etched for rotation about its longitudinal axis, means for rotating said cylinder, means operable to provide a spray of etching fluid which is di rected against a portion of the surface of said cylinder being etched including an elongated tank which contains etching fluid and which has an elongated, relatively narrow throat and means for atomizing the etching fluid within said tank, means for doctoring oir etching fluid and for confining the etching fluid spray to a predetermined portion of the surface of the cylinder which is being etched including a pair of spacedapart elongated, horizontally extending air nozzles, means for adjustably supporting said air nozzles intermediate the throat of said acid tank and the surface of the cylinder being etched, a

supply of pressure air connected to said nozzles, control means interconnected with said nozzles for simultaneously positioning said nozzles to deliver streams of pressure air onto the surface of said cylinder, and indicating means associated with said control means, said indicating means being calibrated for Varying sized cylinders whereby said nozzles can be pre-set in a position wherein said streams of air are directed along lines defined by extended radii of the cylinder being etched.

5. In combination in apparatus for etching printing cylinders of varying sizes, adjustable means for supporting the cylinder to be etched for rotation about its longitudinal axis, means for rotating said cylinder, an elongated tank which contains etching fluid positioned adjacent the surface of the cylinder being etched, said tank having an elongated, relatively narrow throat, means for atomizing the etching fluid within said tank, and means for confining the etching fluid to a predetermined portion of the area of the cylinder including a pair of spaced zles, a source of pressure air, means connecting said source of pressure air to each of said air nozzles, at least one journal section on each of said air nozzles, said air nozzles being disposed intermediate the throat of said acid tank and the surface of the cylinder being etched and being supported for hinged movement about an axis defined by said journal sections, a mechanical control linkage for positioning said nozzle including a gear attached to each of said. journal sections, the gears on opposite air nozzles meshing along the center line of said tank, a control shaft which is provided with gears for meshing with the gears on at least one of said air nozzles, and means for rotating said control shaft thereby simultaneously positioning said nozzles to deliver streams of air onto the surface of the cylinder being etched.

6. In combination in apparatus for etching printing cylinders of varying sizes, adjustable means for supporting the cylinder to be etched fit for rotation about its longitudinal axis, means for rotating said cylinder, an elongated tank which contains etching fluid positioned adjacent the surface of the cylinder being etched, said tank having an elongated, relatively narrow throat, means for atomizing the etching fluid within said tank, and means for confining the etching fluid to a predetermined portion of the area of the cylinder including a pair of spaced apart,

'= elongated, horizontally extending air nozzles, a

source of pressure air, means connecting said source of pressure air to each of said air nozzles, at least one journal section on each of said air nozzles, said air nozzles being disposed intermediate the throat of said acid tank and the surface of the cylinder being etched and being supported for hinged movement about an axis defined by said journal sections, a mechanical control linkage for positioning said nozzle including a gear attached to each of said journal sections, the gears on opposite air nozzles meshing along the center line of said tank, a control shaft which is provided with gears for meshing with the gears on at least one of said air nozzles, means for rotating said control shaft to thereby simultaneously position said nozzles to deliver streams of air onto the surface of the cylinder being etched, and indicating means associated with said control shaft, said indicating means being calibrated for varying sized cylinders whereby said nozzles can be pre-set in a position wherein said streams of pressure air are directed along lines defined by extended radii of the cylinder being etched.

CHARLES L. HENDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,293,201 Gaebel Aug, 18, 1942 2,360,676 Henderson Oct. 1'7, 1944 

